Reliability and Usefulness of the Pressure Pain Threshold Measurement in Patients with Myofascial Pain

OBJECTIVE: To assess the usefulness of a pressure algometer to measure pressure pain threshold (PPT) for diagnosis of myofascial pain syndrome (MPS) in the upper extremity and trunk muscles. METHOD: A group of 221 desk workers complaining of upper body pain participated in this study. Five physiatrists made the diagnosis of MPS using physical examination and PPT measurements. PPT measurements were determined for several muscles in the back and upper extremities. Mean PPT data for gender, side, and dominant hand groups were analyzed. Sensitivity and specificity of Fischer's standard method were evaluated. PPT cut-off values for each muscle group were determined using an ROC curve. RESULTS: Cronbach's alpha for each muscle was very high. The PPT in men was higher than in females, and the PPT in the left side was higher than in the right side for all muscles tested (p<0.05). There was no significant difference in PPT for all muscles between dominant and non-dominant hand groups. Diagnosis of MPS based on Fischer's standard showed relatively high specificity and poor sensitivity. CONCLUSION: The digital pressure algometer showed high reliability. PPT might be a useful parameter for assessing a treatment's effect, but not for use in diagnosis or even as a screening method.